The primary goal of the proposed studies is to gain information concerning the structure and function of the plasma membrane of Neurospora crassa with particular emphasis on the molecular mechanisms of several transport systems which operate in the Neurospora plasma membrane. Specifically, we hope to a) characterize Neurospora plasma membranes with respect to appearance in the electron microscope, macromolecular composition, and enzymatic activities, b) isolate and characterize several transport system components from Neurospora plasma membranes, including plasma membrane ATPase(s) and proteins which are components of the glucose active transport system and the aromatic- neutral amino acid transport system, and c) add the isolated transport system components back to spheroplasts or isolated plasma membrane vesicles to stimulate or reconstitute functional transport systems.